Inderal (Propranolol)

Inderal (propranolol) acts on the cardiovascular and nervous systems to control blood pressure, heart rhythm, and vascular tone.

• Hypertension: lowers systolic and diastolic pressure by reducing cardiac output and renin release.
• Angina pectoris: decreases myocardial oxygen demand, relieving chest pain during exertion.
• Myocardial infarction prophylaxis: reduces risk of recurrent heart attacks by stabilising heart rhythm.
• Cardiac arrhythmias: controls abnormal heartbeats such as atrial fibrillation and ventricular ectopy.
• Migraine prophylaxis: diminishes frequency and severity of migraine attacks.
• Essential tremor: lessens tremor amplitude in patients with neurological tremor disorders.

• Propranolol is a non‑selective β‑adrenergic receptor antagonist that blocks β1 and β2 receptors in the heart, blood vessels, and bronchial smooth muscle. This inhibition reduces heart rate, myocardial contractility, and renin release, leading to decreased cardiac output and lower blood pressure. It also dampens sympathetic nervous system activity, contributing to its anti‑arrhythmic, anti‑anginal, migraine‑preventive, and tremor‑reducing effects.

Common side effects are generally mild and may resolve with continued therapy.

Common Side Effects

• Fatigue or tiredness
• Dizziness or light‑headedness
• Cold hands and feet
• Sleep disturbances, including vivid dreams
• Nausea, abdominal discomfort or diarrhea
• Mild bradycardia (slow heart rate)

Serious or Rare Side Effects

• Severe bradycardia or heart block
• Marked hypotension (low blood pressure)
• Bronchospasm or severe asthma exacerbation
• Hypoglycaemia, especially in diabetic patients on insulin
• Allergic reactions such as rash, angioedema, or anaphylaxis

Before initiating propranolol, clinicians should evaluate patient‑specific risk factors and monitor therapy closely.

• Cardiovascular assessment: confirm stable heart rate and blood pressure before dosing.
• Respiratory evaluation: avoid in patients with uncontrolled asthma or severe chronic obstructive pulmonary disease.
• Diabetes monitoring: watch for masked hypoglycaemia in insulin‑treated patients.
• Concomitant medications: review for drugs that may potentiate bradycardia or hypotension.
• Renal/hepatic function: consider dose adjustment in impaired patients.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Propranolol may interact with several medicines, requiring dose adjustments or avoidance.

Major Interactions (Avoid)

• Asthma or COPD medications: non‑selective β‑blockade can precipitate bronchospasm.
• Severe bradycardia or AV‑block agents: concurrent use may cause dangerous heart rate slowing.
• Calcium‑channel blockers (verapamil, diltiazem): combined effect can lead to profound hypotension and heart block.

Moderate Interactions (Monitor Closely)

• β‑agonist bronchodilators: may reduce bronchodilator efficacy.
• Antidiabetic drugs (insulin, sulfonylureas): increased risk of hypoglycaemia.
• NSAIDs or other antihypertensives: may blunt blood‑pressure‑lowering effect, requiring monitoring.